Still, dominance alone is not an antitrust problem. The issue is the powerful company’s behavior, says Andrew I. Gavil, a professor at the Howard University School of Law. “You have to be big and bad, not just big,” he said.

The telltale signs of a company’s bad behavior include raising prices, hindering innovation and excluding competitors. There is no evidence that Google is engaged in suspect behavior, but it could be hard to spot. Its ad auction system, for example, is essentially a private marketplace run by Google, without much disclosure to advertisers or to Web publishers.

For the record, I think Google is good. But I have a question. What about when Google itself outbids you on Adwords? Now this isn't the biggest thing in the grand scheme of things, but they seem to win every auction I compete in and effectively raise prices.

Still, dominance alone is not an antitrust problem. The issue is the powerful company’s behavior, says Andrew I. Gavil, a professor at the Howard University School of Law. “You have to be big and bad, not just big,” he said.

The telltale signs of a company’s bad behavior include raising prices, hindering innovation and excluding competitors. There is no evidence that Google is engaged in suspect behavior, but it could be hard to spot. Its ad auction system, for example, is essentially a private marketplace run by Google, without much disclosure to advertisers or to Web publishers.

For the record, I think Google is good. But I have a question. What about when Google itself outbids you on Adwords? Now this isn't the biggest thing in the grand scheme of things, but they seem to win every auction I compete in and effectively raise prices.